In recent years, the miniaturization and performance enhancement of electronic equipment have advanced. For multilayer printed wiring boards, in order to improve the packaging density of electronic components, conductor wiring is increasingly made finer, and their wiring formation techniques are desired. As methods for forming high density fine wiring on an insulating layer, an additive method in which a conductor layer is formed only by electroless plating, a semi-additive method in which a thin copper layer is formed on the entire surface by electroless plating, and then a conductor layer is formed by electrolytic plating, and then the thin copper layer is flash-etched, and the like are known.
In addition, due to the miniaturization and densification of multilayer printed wiring boards, thinning laminates used for multilayer printed wiring boards is actively studied. With thinning, the problems of a decrease in packaging reliability and an increase in the warpage of multilayer printed wiring boards occur, and therefore high adhesiveness and high glass transition temperature are require of resin compositions that are materials of insulating layers.
Patent Literatures 1 and 2 describe techniques using an epoxy resin, a phenolic resin, and an imidazole silane in order to improve the adhesiveness between an inner layer circuit and an insulating layer and moldability.
In addition, Patent Literature 3 describes a resin composition using an epoxy resin, a curing agent, silica, and an imidazole silane and discloses that when this resin composition is cured, and a metal layer is formed, by plating treatment, on the surface of the cured product subsequently subjected to roughening treatment, the cured product and the metal layer exhibit high adhesion.